The text being referred to is the “Gospel of Barnabas”. If the book does in fact contain the Gospel of Barnabas, this would be the oldest surviving copy of the text The article is very light on details, suggesting only that it is 1500 years old (though from the pictures I am not sure you would have a codex like that from ca 500), and that it was written in Aramaic (possible). The information in the final paragraph is blatantly false, the Council of Nicaea did not decide the Canon and played no role in adding or deleting books “from the Bible”.

Apart from this text, the Gospel survived only in two manuscripts from the 16th century in Italian and Spanish, the Spanish version now surviving only in a partial transcript from the 18th century. Mention is made of a Gospel of Barnabas in a 6th century Latin and 7th Century Greek list of books. It is unlikely that the Spanish/Italian text dates any earlier than the 14th century, though it may be supposed that an earlier text existed in a different language that formed a source text.

The contents of the gospel seem overall to be closer to Islamic conceptions of Jesus, but not in every detail.

As for your question about Paul, I suppose this depends entirely on what ‘cult’ means in the context of the comment. There is little doubt about a historical Paul, and at least some of his letters are widely considered to be authentic. Paul’s ministry seems largely confined to Gentile populations throughout Asia Minor, Greece, and Italy, which becomes the basis for the majority of the Early Church as the Christian community in Jerusalem becomes destabilised thanks to the Bar Kochba revolt and the destruction of the temple. It is difficult to trace the history of Jewish-background Christians after 70AD. So the Christianity that takes hold in the Roman Empire is to a large degree influenced by Paul’s endeavours.

Since Bauer in 1934 a growing view has been that Heresy proceeds Orthodoxy. Or to put it another way, the idea of a single and unified church only exists because a later unified church portrayed it that way. Rather, in the beginning there are various competing “versions” of Christianity. I think this view appeals to some of our post-modern sensibilities a little too much. This view has come under criticism in recent years, both for its own interpretive “grid”, and also in the details of Bauer’s argument. Kostenberger would be an example of a religious conservative who opposes Bauer on a historical level.

As for your question about Christianity becoming adopted by Rome on an Imperial scale: Constantine I ceases persecution of Christians and appears to adopt Christianity personally, though to varying degrees, in his reign. Christianity becomes personally favoured by the Emperor. This is from 318 onwards. However Christianity is not a majority religion at the time. Why did Constantine adopt it? This is an open question for scholarly debate. Personally, I am inclined to treat Constantine’s situation as a mixture of some kind of religious conversion coupled with a politician pleased to use it for his own purposes. Constantine’s patronage greatly increases the influence of Christianity, and it becomes a majority religion within a few decades. Under Theodosius, from 379 onwards, it becomes the state religion.

Do you want comments on the original article, i.e. about the Gospel of Barnabas, or only on your questions?